With the proliferation of broadband transmission media such as digital satellite television, digital cable, cable modem, and DSL, several error correcting transmission protocols have emerged. Conventional standards like Integrated Services Digital Broadcasting Satellite (ISDB-S) that deploy QuadraPhase-Shift Keying (QPSK) or 8 level Phase-Shift Keying (8PSK) based systems use conventional forward error correction techniques. Such techniques allow transmission of standard and High Definition Digital Television (HDTV) signals over satellite by using a higher bandwidth and transmitting power to be able to deliver digital television channels.
The following TABLE 1 illustrates an example of a conventional target satellite system performance specification:
TABLE 1ItemMinTypMaxUnit1Payload41  ——Mbps2CodeTBD—TBD3QEF10E − 11——4Symbol20  22  23  MSps5Eb/No @ 10E − 1 2/3 or—— 4  dB5/6 or—— 4.6dB8/9—— 5.2dB6Dish——46  cm7Satellite EIRP for+2.6——dB8 PSK with respect toQPSK transponders8C/No for QPSK 20 Msps.—78.9—dB3/4
These specifications can vary based on the broadband carrier environment. Conventional QPSK based transmission systems do not achieve high definition digital television (i.e., 720 p or 1080 i) with the given constraints of bandwidth and available transmission power.
It would be desirable to develop a television system specification in response to system performance goals for the design and development of a Low Density Parity Check (LDPC) code based Forward Error Correction (FEC) system for use in broadband gateways.